title: Comparative immunogenicity of 7 and 13-valent pneumococcal conjugate vaccines and the development of functional antibodies to cross-reactive serotypes.
abstract: BACKGROUND
  Protection against disease or colonization from serotypes related to those in pneumococcal conjugate vaccines (i.e. cross-protection) vary by serotype; the basis for this variation is not understood. The 13-valent pneumococcal conjugate vaccine (PCV13) replaced 7-valent conjugate (PCV7) in the USA in 2010 allowing assessment of PCV7 and PCV13 immunogenicity and functional cross-protection in vitro.
  
  
  METHODS
  Post-primary, pre-booster and post-booster sera from American Indian children receiving exclusively PCV7 or PCV13 were collected. IgG was measured by ELISA for 13 vaccine serotypes; functional antibody was assessed by opsonophagocytic killing assays for serotypes 6A/B/C and 19A/F.
  
  
  RESULTS
  Post-primary IgG geometric mean concentrations (GMC) for serotypes 4 and 9V were lower in PCV13 recipients while 19F GMCs were higher. Only 19F differences persisted after receipt of the booster dose. Functional antibody activity was higher among PCV13 recipients for 6A, 6C, 19A and 19F (p<0.04), and among PCV7 recipients for 6B (p = 0.01). Following PCV7, functional antibodies to 6A but not 19A were observed. High levels of 6C functional activity were seen after PCV13 but not PCV7.
  
  
  CONCLUSIONS
  Functional antibody activity against 6A/B/C and 19A/F suggest that PCV13 is likely to control the 19A disease and 6C disease remaining despite widespread use of PCV7.
authors.affiliation: Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America.
authors.forename: Lindsay R
authors.initials: LR
authors.lastname: Grant
authors.forename: Sarah E
authors.initials: SE
authors.lastname: O'Brien
authors.forename: Polly
authors.initials: P
authors.lastname: Burbidge
authors.forename: Mitch
authors.initials: M
authors.lastname: Haston
authors.forename: Marta
authors.initials: M
authors.lastname: Zancolli
authors.forename: Lucy
authors.initials: L
authors.lastname: Cowell
authors.forename: Marina
authors.initials: M
authors.lastname: Johnson
authors.forename: Robert C
authors.initials: RC
authors.lastname: Weatherholtz
authors.forename: Raymond
authors.initials: R
authors.lastname: Reid
authors.forename: Mathuram
authors.initials: M
authors.lastname: Santosham
authors.forename: Katherine L
authors.initials: KL
authors.lastname: O'Brien
authors.forename: David
authors.initials: D
authors.lastname: Goldblatt
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology*; D002648:Child; D003429:Cross Reactions / Q000276:immunology*; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007114:Immunization; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007223:Infant; D008297:Male; D022242:Pneumococcal Vaccines / Q000276:immunology*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000276:immunology*; D018074:Vaccines, Conjugate / Q000276:immunology*
chemical_list: C538862:13-valent pneumococcal vaccine; D000907:Antibodies, Bacterial; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D007074:Immunoglobulin G; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate